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Ask Slashdot: How To Unblock Email From My Comcast-Hosted Server?
New submitter hawkbug writes For the past 15 years, I have hosted my own email server at home and it's been pretty painless. I had always used a local Denver ISP on a single static IP. Approximately two years ago, I switched to a faster connection, which now is hosted on Comcast. They provide me 5 static IPs and much faster speeds. It's a business connection with no ports blocked, etc. It has been mostly fine these last two years, with the occasional outage due to typical Comcast issues. About two weeks ago, I came across a serious issue. The following email services started rejecting all email from my server: Hotmail, Yahoo, and Gmail. I checked, and my IP is not on any real time blacklists for spammers, and I don't have any security issues. My mail server is not set as an open relay, and I use SPF records and pass all SPF tests. It appears that all three of those major email services started rejecting email from me based on a single condition: Comcast. I can understand the desire to limit spam — but here is the big problem: I have no way to combat this. With Gmail, I can instruct users to flag my emails as "not spam" because the emails actually go through, but simply end up in the spam folder. Yahoo and Hotmail on the other hand, just flat out reject the traffic at lower level. They send rejection notices back to my server that contain "tips" on how to make sure I'm not an open relay, causing spam, etc. Since I am not doing any of those things, I would expect some sort of option to have my IP whitelisted or verified. However, I can not find a single option to do so. The part that bugs me is that this happened two weeks ago with multiple major email services. Obviously, they are getting anti-spam policies from a central location of some kind. I don't know where. If I did, I could possibly go after the source and try to get my IP whitelisted. When I ask my other tech friends what they would do, they simply suggest changing ISPs. Nobody likes Comcast, but I don't have a choice here. I'm two years into a three-year contract. So, moving is not an option. Is there anything I can do to remedy this situation?
And say what exactly? They are not the problem. It's the other email providers blocking me simply because I'm on a Comcast IP.
Now you know how it feel to be Russian or Chinese and have your mail rejected just because of the ip address you have.
It may be that when one users complains, they block ALL email from your server; not just mail to the complaining account holder.
One thing I forgot to mention, in reading the other replies people are claiming that google at least requires DKIM in that they reject all mail without a valid DKIM. My server is setup to use both SPF and DKIM and I'm not having problems.
Greetings.
I have a Comcast Xfiniti Business line, 5 static IP addresses, etc. It sounds like our mutual set ups are equivalent. I've been running my email servers in my own domains since 1998, through some gone ISP, PacBell/AT&T, and Comcast without issues.
Contact the Comcast business line. Have your actual account ready -- you can get that from the Comcast Business web page for your account. Those numbers changed in the last 12 months to a shorter, simpler format. Request technical support and discuss the issue.
One thing that you MUST do if you want to run your own email: request that Comcast set reverse DNS to point at your servers for the non-authoritative request. A reverse DNS request to your IP address must return the name you use for your primary (and secondary, and so on) MX records. If that's set up, then you've solved 90% of the issues with Gmail and Yahoo!.
As far as Hotmail: they've been rejecting my email unless users white list my address(es) in their individual accounts. This has happened since Microsoft bought them. No way around that, and no appeals; every time I tried to contact them I might as well have sent the emails/requests through a black hole.
Source: 8+ years with Comcast Business, and I moved to a new location (with new IP addresses and new routers) 12 days ago. It took them 10 minutes to set the rDNS and propagate. Within an hour it was resolving fine and any lagging email issues were resolved (36 hours of some undelivered messages).
Google my name "Eugene Ciurana" and ping me through my contact page if you want some assistance with your set up and/or other tips w/dealing with Comcast. I've been a very happy customer with them (they fixed my lines, including physical cable modem replacement due to physical failure, while I was out of the country last January and coordinating with someone who could open the door to them and so on), and in general found that, if you explain what you need and why, their tech guys do work with you to solve issues. The key is understanding that *you* may know more about networking/server set up than their tech guys, so if you aren't specific about what you want they may not grok what you need.
Dear admins: WTF is a lameness filter? What is it filtering? I couldn't offer complete information to this guy because of the Comcast support number and/or IP addresses I listed. With my Karma level and the number of years I've been around, your system ought to be configured to let stuff through w/o issue. Look at my user ID. Thanks.
Cheers!
http://eugeneciurana.com | http://ciurana.eu